I’d like to introduce two kinds of software, one for windows users and another for Mac OS users.
In general, QuickSilver and FastOpen are both utilities which accelerate access to whatever you need, such as frequently used files and directories, or applications hidden in the depth of your system, etc. Here are the differences and the similarities.
Similarities:
1. Provide accelerated access to frequently used files and directories.
2. Use hotkey to summon, and the hotkey can easily be changed.
3. Almost complete replacement for the Start menu.
4. Take very few resources, when you are not working with them, they stay in idle mode
Differences:
1. Quicksilver for Mac OS users; FastOpen for Windows users.
2. In-app plug-ins can be freely installed with QS, which means you don't have to bloat up QS with functions you won't use, but you do need to install plug-ins for data types you want to access.
FastOpen provides convenient functions such as Web Search, Dictionary, Weather Forecast, Web Browser, E-mail, DOS Command, and File Browser. But you can uninstall either of them.
3. FastOpen occupies a larger size of 10.3 MB while QuickSilver a smaller size of 1.73 MB.

For Mac OS users, QS is a must-have utility. The only pity is that it doesn’t support for Windows. But now, Windows users have the alternative to manage a menu of files, folders and web address, and can display an unlimited number of menu items and menus. FastOpen is easy to use and let you design menus that work just like the Start menu. It makes Windows better.